Lately I have noticed these machines calling for toner replacemet a little premature. The cartridge that was replaced still has toner in it. Not alot, but enough to supply the dev with for a while longer. We use the compatible toner with the blue cap. If it were just one machine, I would think the issue is with that machine, but it is with several machines. Once a new cartridge is installed all is well for a long time until it get low in the cartridge. Just wondering if anyone has seen this?